Masumi is one of the great names of the sake world, admired throughoutJapan for its satisfying taste and unshakeable, down-to-earth reliability. The brewery where it is made was founded in 1662 in the town of Suwa, where a tradition of precision craftsmanship had led to the development of the silk spinning trade. Attention to detail remains at the heart of the Masumi brewing philosophy to this day.

In 1920, the brewery's president, Masaru Miyasaka, appointed a 28-year-old sake prodigy named Chisato Kubota to the position of brewmaster. The two travelled throughout Japan in the manner of Zen monks, "knocking on the door of the master and seeking knowledge." This keen desire to elevate the quality of Masumi sake, combined with a shared openness of mind, was rewarded in 1936 when Miyasaka Brewing Company won the first of many top honors at the Japan National Sake Appraisal.

Masumi achieved even greater prominence in 1946 when brewmaster Kubota, discovering a lovely aroma emanating from one of the brewery's fermentation tanks, requested that an expert from the National Research Institute of Brewing be called in for consultation. Samples were taken and it was soon confirmed that a new yeast variety, Association No. 7, had been discovered.

In the sake world, discovering a new yeast is like receiving the NobelPrize, and only a handful of breweries enjoy this distinction. With its gentle, pleasing aroma and ease of use, No. 7 soon spread beyond Nagano Prefecture, and today continues to be used by over half of the breweries in Japan. In 2002, Masumi released a redolent, old-style sake with an insouciant 21st-century attitude called "Nanago" (No. 7) in tribute to the famous microorganism to whom the sake world owes so much.